Alignment method for a vehicle wireless charging structure

ABSTRACT

An alignment method for a vehicle wireless charging system, that includes detecting reception of electromagnetic radiation received by a vehicle-side coil from a transmitter coil with the vehicle-side coil at a current position relative to the transmitter coil. Other steps include determining efficiency of electromagnetic radiation reception by the vehicle-side coil, and determining whether or not the efficiency of electromagnetic radiation reception by the vehicle-side coil achieves a predetermined level of reception efficiency. Further steps include repositioning the vehicle-side coil in response to determining that the efficiency of the electromagnetic radiation reception is less than the predetermined level of reception efficiency, and repeating the determining of the efficiency of electromagnetic radiation reception and the repositioning the vehicle-side coil until the determined efficiency is equal to or greater than the predetermined level of reception efficiency.

BACKGROUND

Field of the Invention

The present invention generally relates to an alignment method for avehicle wireless charging structure. More specifically, the presentinvention relates to a method for aligning a vehicle-side induction coilwith a fixed transmission coil in order charge a battery of the vehiclewith optimal efficiency.

Background Information

A vehicle wireless charging system includes a charging station that istypically installed with a garage or carport and includes a transmissioncoil configured to emit electromagnetic radiation received by areceiving coil on a vehicle for purposes of recharging a battery of thevehicle. Such wireless systems typically include a positioning mechanismas a part of the charging station for aligning the transmission coilwith the receiving coil on the vehicle after the vehicle has been parkedwithin the garage or carport. A problem with such an arrangement is thatwhen the receiving coil is located along an underside of the vehicle,the transmission coil and its positioning structure must be installedbelow an exposed surface of a floor of the garage or carport. Theinstallation of the transmission coil and positioning structure belowthe level of the floor of the charging station can be costly anddifficult.

SUMMARY

One aspect of the current disclosure is to provide a receiving coilinstalled to an underside of the vehicle that includes an alignmentassembly with methodology for automatically aligning the receiving coilwith a floor mounted transmission coil once the vehicle has been parkedabove the transmission coil.

In view of the state of the known technology, one aspect of the presentdisclosure is to provide an alignment method with a vehicle wirelesscharging system. The method includes detecting reception ofelectromagnetic radiation received by a vehicle-side coil from atransmitter coil with the vehicle-side coil at a current positionrelative to the transmitter coil. The method further includesdetermining efficiency of electromagnetic radiation reception by thevehicle-side coil, and determining whether or not the efficiency ofelectromagnetic radiation reception by the vehicle-side coil achieves apredetermined level of reception efficiency. The method further includesrepositioning the vehicle-side coil in response to determining that theefficiency of the electromagnetic radiation reception is less than thepredetermined level of reception efficiency, and repeating thedetermining of the efficiency of electromagnetic radiation reception andthe repositioning the vehicle-side coil until the determined efficiencyis equal to or greater than the predetermined level of receptionefficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a side schematic view of a vehicle wireless charging structureincluding a transmission charging assembly and a vehicle, thetransmission charging assembly having a power controller and atransmission coil installed to respective surfaces of a parking area,the vehicle having an alignment assembly with a controller and avehicle-side induction coil (a reception coil) in accordance with afirst embodiment;

FIG. 2 is a top schematic view of the vehicle wireless chargingstructure showing the power controller and the transmission coil of thetransmission charging assembly installed within the parking area, andshowing the vehicle-side induction coil and the controller of thealignment assembly of the vehicle in phantom overlaying the transmissioncoil in accordance with the first embodiment;

FIG. 3 is a side schematic view of a portion of the vehicle wirelesscharging structure showing the alignment assembly with the vehicle-sideinduction coil located above the transmission coil in accordance withthe first embodiment;

FIG. 4 is a front schematic view of the portion of the vehicle wirelesscharging structure shown in FIG. 3, showing the alignment assembly withthe vehicle-side induction coil located above the transmission coil inaccordance with the first embodiment;

FIG. 5 is a perspective view of the alignment assembly shown removedfrom the vehicle showing a first track structure and linear supportstructures that support a first shield plate to an underside surface ofthe vehicle in accordance with the first embodiment;

FIG. 6 is a perspective view of one of the linear support structures ofthe alignment assembly shown removed from the alignment assembly inaccordance with the first embodiment;

FIG. 7 is an exploded perspective view of the alignment assembly showingthe first track structure, a pair of linear support structures, a firstpositioning device, the first shield plate, a second track structure,another pair of linear support structures, a second positioning device,a second shield plate and the vehicle-side induction coil in accordancewith the first embodiment;

FIG. 8 is a flowchart depicting operational steps performed by the powercontroller of the transmission charging assembly during operation of thetransmission coil in accordance with the first embodiment;

FIG. 9 is a flowchart depicting operational steps performed by thecontroller of the vehicle in determining whether or not a battery of thevehicle needs to be charged and whether or not the vehicle is parkedabove the transmission coil in accordance with the first embodiment;

FIG. 10 is a flowchart depicting operational steps performed by thecontroller of the vehicle in preparation for aligning the vehicle-sideinduction coil with the transmission coil in accordance with the firstembodiment;

FIG. 11 is a flowchart depicting operational steps performed by thecontroller of the vehicle in the aligning of the vehicle-side inductioncoil with the transmission coil prior to charging of the battery inaccordance with the first embodiment;

FIGS. 12a thru 12 e are schematic views showing movement of thevehicle-side induction coil as performed by the controller in the stepsdepicted in FIG. 11 along a first axis (in a vehicle longitudinaldirection) in accordance with the first embodiment;

FIGS. 13a thru 13 e are further schematic views showing movement of thevehicle-side induction coil as performed by the controller in the stepsdepicted in FIG. 11 along a second axis (in a vehicle lateral direction)perpendicular to the first axis in accordance with the first embodiment;and

FIG. 14 is an exploded perspective view of an alignment assembly showinga first track structure, a pair of linear support structures, a firstpositioning device, a first shield plate, a second track structure,another pair of linear support structures, a second positioning device,a second shield plate and a vehicle-side induction coil in accordancewith a second embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings. It will be apparent to those skilled in the art from thisdisclosure that the following descriptions of the embodiments areprovided for illustration only and not for the purpose of limiting theinvention as defined by the appended claims and their equivalents.

Referring initially to FIG. 1, a wireless charging structure 10 thatincludes a transmission charging assembly 12 and a vehicle 14 having areception charging assembly 16 is illustrated in accordance with a firstembodiment.

The wireless charging structure 10 is designed such that when thevehicle 14 is parked above a portion of the transmission chargingassembly 12, a battery B within the vehicle 14 can be charged. Thevehicle 14 includes structure that automatically aligns the receptioncharging assembly 16 with the transmission charging assembly 12 suchthat transmission of energy from the transmission charging assembly 12to the reception charging assembly 16 is optimized, thereby improvingthe process of re-charging the battery B, as is described in greaterdetail below.

As shown in FIGS. 1 and 2, the transmission charging assembly 12includes elements that are installed in a parking area P dimensioned toreceive the vehicle 14. The parking area P can be a driveway, a privategarage space, a commercial garage space or carport and includes ahorizontally oriented surface S and a vertical wall W. It should beunderstood from the drawings and the description herein that the surfaceS can be a level surface, but a level orientation is not required. Thetransmission charging assembly 12 can alternatively be installed to aparking area with a surface S that has a slight incline. In the depictedembodiment, the surface S is depicted as being level. The parking area Pincludes a space sufficiently large to receive the vehicle 14.

As is further shown in FIGS. 1 and 2, the transmission charging assembly12 includes a power controller 20, a transmission coil 22, a pair ofwheel chocks or stops 24 and a cable C connecting the power controller20 to the transmission coil 22. In the depicted embodiment, the powercontroller 20 is mounted to the vertical wall W. Alternatively the powercontroller 20 can be located remote relative to the parking area P, orcan be a free-standing unit connected to household circuitry. Forexample, the power controller 20 can be installed in a closet, basementarea or other enclosed area (not shown) remote from the parking area P.Further, the power controller 20 can be installed as a free-standingrecharging station located in a commercial parking area with a dedicatedparking space adjacent thereto.

The power controller 20 of the transmission charging assembly 12includes a power supply (not shown) connected to, for example, acommercial electricity power source that is preferably 220 volts AC, butcan provide current at voltage levels greater or less than 220 volts,depending upon available electric power. The power controller 20 alsoincludes circuitry and pre-programmed control logic that enables thepower controller 20 to wirelessly communicate with the receptioncharging assembly 16 of the vehicle 14 in a manner described in greaterdetail below.

The transmission coil 22 is fixedly and non-movably attached to thesurface S within the parking area P at a predetermined location. Thestops 24 are also fixedly attached to surface S of the parking area P,but can be configured for removal and repositioning. The stops 24 areinstalled to the surface S of the parking area P in predeterminedlocations relative to the transmission coil 22 and relative to thelocation of the reception charging assembly 16 of the vehicle 14.Specifically, the stops 24 are positioned relative to the transmissioncoil 22 such that when the vehicle 14 is driven into the parking area P,front wheels 28 of the vehicle contact the stops 24 thereby restrictingfurther movement of the vehicle 14, thereby assisting the vehicleoperator during parking maneuvers of the vehicle 14 such that thevehicle 14 is parked in or close to a predetermined location. Thispredetermined location is such that portions of the reception chargingassembly 16 of the vehicle 14 are located above the transmission coil 22in an approximate alignment position once parked. An example of theapproximate alignment position is depicted in, for example, FIG. 12a andis described in greater detail below. As shown in FIG. 2, the parkingarea P can also include lines that assist the vehicle operator inpositioning of the vehicle 14 in the parking area.

As shown in FIG. 1, the vehicle 14 includes a vehicle body structure 29,a power plant 30, the battery B and the reception charging assembly 16.The reception charging assembly 16 includes a controller 32, analignment assembly 34 and cables 36, 37 and 38. The cable 36 connectsthe reception charging assembly 16 with the controller 32. The cable 37connects the controller 32 with the power plant 30 and the cable 38connects the battery B with the controller 32 and the power plant 30.

The power plant 30 is supported in a conventional manner within thevehicle body structure 20 and includes an electric motor that providesrotary power to the vehicle 14 in a conventional manner. Since electricmotors for vehicles are conventional vehicle devices, furtherdescription is omitted for the sake of brevity. Alternatively, the powerplant 30 can be a hybrid motor that includes an internal combustionengine that operates in concert with an electric motor in a conventionalmanner. The power plant 30 receives electric power from the battery B ina conventional manner.

The battery B is a rechargeable battery that is recharged by thereception charging assembly 16 in a manner described in greater detailbelow. Although not shown, the battery B can also be recharged via anelectric connector (not shown) provided on the vehicle 14 such that thebattery B is recharged via a direct electrical connection via thecontroller 32 and the electric connector. However, in the depictedembodiment, the battery B is primarily recharged via the wirelesscharging structure 10, where electromagnetic energy is transmitted bythe transmission coil 22 and is received by the reception chargingassembly 16 of the vehicle 14 in a manner described in greater detailbelow.

The controller 32 includes voltage convertor circuit that convertsalternating current transmitted by the transmission coil 22 into directcurrent used to charge the battery B. The controller 32 also includescircuitry (such as a micro-computer) that is programmed to operate thereception charging assembly 16 during an alignment process that isdescribed in greater detail below. The circuitry of the controller 32 isalso configured to communicate with the power controller 20 of thetransmission charging assembly 12 via any of a plurality ofcommunication methods and structures. For example, the power controller20 and the controller 32 can each include wireless communication devicessuch as Bluetooth® devices, Wi-Fi devices, or can be configured towirelessly communicate with one another via transmissions between thetransmission coil 22 and the reception charging assembly 16. Since suchwireless communication capabilities are conventional technologies,further description is omitted for the sake of brevity.

As shown in FIGS. 1 and 2, the alignment assembly 34 is mounted directlyto the vehicle 14. In the depicted embodiment, the alignment assembly 34is mounted to the underside of the vehicle 14, but can alternatively bemounted within the body structure of the vehicle 14, so long as thealignment assembly 34 is mounted to a location of the vehicle 14 thatdoes not interfere with reception of electromagnetically transmittedenergy from the transmission coil 22.

In the depicted embodiment, the alignment assembly 34 is fixedlyattached to the underside of the vehicle 14. The alignment assembly 34is centrally located beneath, for example, the front seats (not shown)of the vehicle 14. It should be understood from the drawings and thedescription herein that the actual installed location of the alignmentassembly 34 can vary from vehicle to vehicle and is not limited to thedepicted location. For example, the alignment assembly 34 canalternatively be installed to a front end, a rear end, a side panel orthe roof panel of the vehicle 14 with the transmission coil 22 beinginstalled to an appropriate corresponding location within the parkingarea P.

One aspect of the actual location of the alignment assembly 34 withrespect to the vehicle 14, is the location of the front wheels 28relative to a reference point 40 on the alignment assembly 34. Forpurposes of understanding the wireless charging structure 10, thereference point 40 is a point along the front edge of the alignmentassembly 34 that is centrally located with respect to the alignmentassembly 34. However, it should be understood from the drawings and thedescription herein, that the reference point 40 is an arbitrary pointchosen for the expressed purpose of proper installation of elements ofthe wireless charging structure 10 with respect to one another, and isnot an absolute fixed location.

A first distance D₁ is defined in a vehicle longitudinal direction D_(L)between a lower tread portion of the front wheels 28 and the referencepoint 40. Second and third distances D₂ and D₃ are defined in vehiclelateral directions Ds (laterally side to side relative to the vehicle14) between a center of respective ones of the front wheels 28 of thevehicle 14 and the reference point 40.

Further, the transmission coil 22 is provided with a similar referencepoint at a front edge thereof. In FIG. 2 the reference point 40 of thealignment assembly 34 and a reference point of the transmission coil 22coincide. Therefore, only the reference point 40 is visible in FIG. 2.When the transmission coil 22 and the stops 24 are installed to thesurface S of the parking area P, the first, second and third distancesD₁, D₂ and D₃ are used to position the transmission coil 22 and thestops 24 relative to one another.

Specifically, the relative positioning of the transmission coil 22 andthe stops 24 is directly determined by the distances between thealignment assembly 34 and the front wheels 28 and relative to parkinglines on the surface S of the parking area P. The stops 24 are installedto the surface S with a distance in the vehicle lateral direction Lsbetween respective centers thereof that is equal to the second distanceD₂ plus the third distance D₃, as shown in FIG. 2. Thereafter, thetransmission coil 22 is positioned and fixedly installed with its frontcenter (the reference point) being located in the vehicle lateraldirections Ds the second distance D₂ from a first one of the frontwheels 28 and is located the third distance D₃ from a second one of thefront wheels 28. Further, the transmission coil 22 is positionedrelative to the vehicle longitudinal direction D_(L) with its frontcenter (the reference point) being located the first distance D₁ fromthe surface of the stops 24.

Consequently, when the vehicle 14 is parked on the surface S above thetransmission coil 22, with the front wheels 28 contacting the stops 24,the alignment assembly 34 will be located above the transmission coil22. However, the location of the alignment assembly 34 may not beperfectly centered above the transmission coil 22 with the vehicle 14parked due to the size of the vehicle 14 and the fact that the vehicleoperator cannot see the alignment assembly 34 and the transmission coil22 while parking the vehicle 14. The final parked location of thevehicle 14 will likely vary slightly each time the vehicle 14 is drivenand then returned and parked on the surface S. Therefore, once thevehicle 14 is parked, the alignment assembly 34 will overlap thetransmission coil 22, but will not necessarily be perfectly alignedtherewith, for example, as depicted in FIG. 2. If the alignment assembly34 is not properly centered (or close to being centered within apredetermined tolerance) above the transmission coil 22, then rechargingefficiency may not be optimal. This situation is referred to as theabove mentioned approximate alignment position, where the alignmentassembly 34 is located above the transmission coil 22, but is notprecisely aligned within predetermined tolerances. Therefore, thealignment assembly 34 is configured to more closely align itself withthe transmission coil 22, as described in greater detail below.

A description of the alignment assembly 34 is now provided with specificreference to FIGS. 3-7. The alignment assembly 34 is depictedschematically in FIGS. 3 and 4, attached to an underside surface 44 ofthe vehicle 14.

The alignment assembly 34 basically includes an outer cover 48, a firsttrack structure 50, a first shield plate 52, a first positioning device54, a second track structure 56, a second shield plate 58, a secondpositioning device 60 and a vehicle-side induction coil 62.

The outer cover 48 is a protective cover that primarily serves toprotect the various components of the alignment assembly 34. The outercover 48 is composed of, for example, a non-conductive material thatdoes not interfere with the transmission and reception ofelectromagnetic radiation (power transmissions) from the transmissioncoil 22 to the vehicle-side induction coil 62. The outer cover 48 isdimensioned and shaped to cover the first track structure 50, the firstshield plate 52, the first positioning device 54, the second trackstructure 56, the second shield plate 58, the second positioning device60 and the vehicle-side induction coil 62. Further the outer cover 48 isdimensioned such that it does not interfere with movement of any of theelements of the alignment assembly 34 throughout the entire range ofmovement of the first shield plate 52 and the second shield plate 58during the alignment process described below. The outer cover 48 isdirectly attached to the underside surface 44 of the vehicle 14 viafasteners (not shown) in a conventional manner.

As shown in FIGS. 3, 5 and 7, the first track structure 50 includes afixed track member 50 a and a slider 50 b that is installed within thefixed track member 50 a such that the slider 50 b can freely slidelinearly along the fixed track member 50 a. One of the fixed trackmember 50 a and the slider 50 b is coated with a frictionless material,such as, for example, polytetrafluoroethylene (PTFE) or other similarfriction reducing material. In the depicted embodiment, the slider 50 bis retained within the fixed track member 50 a by narrowed lower endsthat prevent lateral movement of the slider 50 b in directionsperpendicular to the length of the fixed track member 50 a.Specifically, since the fixed track member 50 a extends in the vehiclelongitudinal direction D_(L), the first shield plate 52 is preventedfrom moving in the vehicle lateral directions Ds. However, the slider 50b can freely slide along the length of the fixed track member 50 a. Thefixed track member 50 a is rigidly attached to the underside surface 44of the vehicle body structure 29 via, for example, mechanical fasteners(not shown). The slider 50 b is rigidly attached to an upper surface 52a (a first side) of the first shield plate 52 via, for example,mechanical fasteners (not shown).

The first track structure 50 can further include at least one andpreferably two linear support structures 64 as shown in FIGS. 5-7. Thelinear support structures 64 define additional track structures that areparallel to the fixed track member 50 a and the slider 50 b when all areinstalled within the alignment assembly 34. Each of the linear supportstructures 64 includes an upper slider 64 a and a lower slider 64 b, asshown in FIG. 6. The lower slider 64 b can freely slide along the upperslider 64 a. Surfaces of one or both of the lower slider 64 b and theupper slider 64 a that slidably contact one another can be provided witha frictionless material, such as, for example, polytetrafluoroethylene(PTFE) or other similar friction reducing material. The upper sliders 64a are fixedly attached to the underside surface 44 of the vehicle bodystructure 29 via, for example, mechanical fasteners (not shown). Thelower sliders 64 b are rigidly fixed to the upper surface 52 a of thefirst shield plate 52 via, for example, mechanical fasteners (notshown).

The first track structure 50 (the fixed track member 50 a and the slider50 b) defines a first axis A₁ (FIGS. 5 and 7) that corresponds to and/oris parallel to the vehicle longitudinal direction D_(L). Morespecifically, the slider 50 b is movable along the first axis A₁. Theslider 50 b is configured to slide along the first axis A₁ along thelength of the fixed track member 50 a. The linear support structures 64of the first track structure 50 extend parallel to the first axis A₁.Hence, the lower sliders 64 b are configured to slide in directionsparallel to the first axis A₁ along the upper sliders 64 a. The linearsupport structures 64 provide support and add stability to movement ofthe first shield plate 52 along the fixed track member 50 a. The linearsupport structures 64 also prevent rotation about the first axis A₁.

The fixed track member 50 a and slider 50 b are elements that provideprecision positioning of the first shield plate 52 when the first shieldplate 52 is moved and positioned by the actions of the first positioningdevice 54 (described in greater detail below). Whereas, the linearsupport structures 64 are provided for support of the first shield plate52 and other elements supported by the first shield plate 52.

The fixed track member 50 a, the slider 50 b and the linear supportstructures 64 support the first shield plate 52 such that the firstshield plate 52 can be moved along the first axis A₁ (in the vehiclelongitudinal direction D_(L)) and positioned with precision by the firstpositioning device 54, as is described in greater detail below.

As mentioned above, the first shield plate 52 is fixed to the slider 50b and the lower sliders 64 b. Consequently, the first shield plate 52 ismovably connected to the underside surface 44 of the vehicle 14 forlinear movement with respect thereto via the support of the slidingmovement of the slider 50 b along the fixed track member 50 a and thesliding movement of the lower sliders 64 b along the upper slider 64 a.More specifically, the first shield plate 52 is supported by the firsttrack structure 50 only for movement along the first axis A₁ (thevehicle longitudinal direction D_(L)).

The first shield plate 52 is made of a material or can include layer ofa material that prevents transmission of electromagnetic radiation froma lower surface 52 b (a second side) to the upper surface 52 a (thefirst side) of the first shield plate 52. The first shield plate 52 islonger in the vehicle longitudinal direction D_(L) and wider in thevehicle lateral directions Ds than the vehicle-side induction coil 62and the transmission coil 22, as is shown in FIGS. 3 and 4. Hence, thefirst shield plate 52 extends outward beyond an outer periphery of thevehicle-side induction coil 62 throughout an entire range of movement ofthe first shield plate 52. Consequently, the first shield plate 52provides a shielding effect that prevents electromagnetic radiation frompenetrating the vehicle body structure 29 and passing into the passengercompartment of the vehicle 14.

The first positioning device 54 includes a housing 54 a and a shaft 54b. In the depicted embodiment, the first positioning device 54 isbasically a stepper motor or other positioning device that can preciselymove and position an object connected thereto to a plurality ofpositions within a predetermined tolerance. In the alignment assembly34, the first positioning device 54 can achieve precise linearpositioning movement of the first shield plate 52 to within, forexample, ±1.0 mm. The shaft 54 b of the first positioning device 54 ismoved linearly via worm gears (not shown) and/or other linear movementstructures to effect movement and positioning of the first shield plate52. Since stepper motors are conventional electro-mechanical devices,further description is omitted for the sake of brevity.

The housing 54 a of the first positioning device 54 is fixedly attachedto the underside surface 44 of the vehicle 14. The shaft 54 b is fixedlyconnected to the slider 50 b. Since the slider 50 b (which defines thefirst axis A₁) is attached to the first shield plate 52, movement of theslider 50 b by the first positioning device 54 causes correspondinglinear movement of the first shield plate 52 along the first axis A₁ (inthe vehicle longitudinal direction D_(L)).

A description of the second track structure 56 and the second shieldplate 58 is now provided with specific reference to FIGS. 4-7. Thesecond track structure 56 includes a fixed track member 56 a and aslider 56 b that is installed within the fixed track member 56 a suchthat the slider 56 b can freely slide along the fixed track member 56 a.One of the fixed track member 56 a and the slider 56 b is coated with africtionless material, such as, for example, polytetrafluoroethylene(PTFE) or other similar friction reducing material. In the depictedembodiment, the slider 56 b is retained within the fixed track member 56a by narrowed lower ends that prevent lateral movement (no movement indirections perpendicular to the length of the fixed track member 56 a).The fixed track member 56 a is rigidly attached to the lower surface 52b of the first shield plate 52 via, for example, mechanical fasteners(not shown). The slider 56 b is rigidly attached to an upper surface 58a (a first side) of the second shield plate 58 via, for example,mechanical fasteners (not shown).

The second track structure 56 can further include at least one andpreferably two linear support structures 66. The linear supportstructures 66 define further track structures that are parallel to thefixed track member 56 a and the slider 56 b when all are installedwithin the alignment assembly 34. Each of the linear support structures66 includes an upper slider 66 a and a lower slider 66 b, as shown inFIG. 6. The lower slider 66 b can freely slide along the upper slider 66a. Surfaces of one or both of the lower slider 66 b and the upper slider66 a that slidably contact one another can be provided with africtionless material, such as, for example, polytetrafluoroethylene(PTFE) or other similar friction reducing material. The upper sliders 66a are fixedly attached to the lower surface 52 b of the first shieldplate 52 via, for example, mechanical fasteners (not shown). The lowersliders 66 b are rigidly fixed to the upper surface 58 a of the secondshield plate 58 via, for example, mechanical fasteners (not shown). Thelinear support structure 66 also prevent rotation of the second shieldplate 56 about the second axis A₂.

The second track structure 56, including the fixed track member 56 a andthe slider 56 b, extend along a second axis A₂ defined by the slider 56b. The second axis A₂ extends in the vehicle lateral directions Ds andis transverse and perpendicular to the first axis A₁ (the vehiclelongitudinal direction D_(L)). The slider 56 b is configured to slidealong the second axis A₂ and along the length of the fixed track member56 a. Further, the linear support structures 66 are parallel to theslider 56 b and the second axis A₂ such that the lower sliders 66 b areconfigured to slide parallel to the slider 56 b and along the uppersliders 64 a. The linear support structures 66 provide support and addstability to movement of the second shield plate 58 along the fixedtrack member 56 a.

The fixed track member 56 a and slider 56 b are elements that provideprecision positioning of the second shield plate 58 when the secondshield plate 58 is moved and positioned by the actions of the secondpositioning device 60. Whereas, the linear support structures 66 areprovided for support of the second shield plate 58 and other elementssupported by the second shield plate 58.

The fixed track member 56 a, the slider 56 b and the linear supportstructures 66 support the second shield plate 58 such that the secondshield plate 58 can be moved along the second axis A₂ (the vehiclelateral direction D_(S)) and positioned with precision by the secondpositioning device 60, as is described in greater detail below.

As mentioned above, the slider 56 b and the lower sliders 66 b are fixedto the upper surface 58 a of the second shield plate 58. Consequently,the second shield plate 58 is movably connected to the lower surface 52b of the first shield plate 52 for linear movement with respect theretovia the support of the sliding movement of the slider 56 b along thefixed track member 56 a and the sliding movement of the lower sliders 66b along the upper slider 66 a. More specifically, the second shieldplate 58 is supported by the second track structure 56 for movementalong the second axis A₂ (the vehicle lateral direction D_(S)) relativeto the first shield plate 52.

Like the first shield plate 52, the second shield plate 58 is made of amaterial or can include a layer of a material that prevents transmissionof electromagnetic radiation from a lower surface 58 b (a second side)to the upper surface 58 a (the first side) of the second shield plate58. The second shield plate 58 is longer in the vehicle longitudinaldirection D_(L) and wider in the vehicle lateral directions Ds than thevehicle-side induction coil 62 and the transmission coil 22, as is shownin FIGS. 3 and 4. Hence, like the first shield plate 52, the secondshield plate 58 extends outward beyond an outer periphery of thevehicle-side induction coil 62 throughout an entire range of movement ofthe second shield plate 58 relative to the first shield plate 52.Consequently, the second shield plate 58 also provides a shieldingeffect that prevents electromagnetic radiation from penetrating thevehicle body structure 29 and passing into the passenger compartment ofthe vehicle 14.

The second positioning device 60 includes a housing 60 a and a shaft 60b. In the depicted embodiment, the second positioning device 60 isbasically a stepper motor or other positioning device that can preciselymove an object connected thereto to a plurality of positions within apredetermined tolerance. In the alignment assembly 34, the secondpositioning device 60 can achieve precise linear positioning movement ofthe second shield plate 58 to within, for example, plus or minus 1.0 mm.The shaft 60 b of the second positioning device 60 is moved linearly viaworm gears (not shown) and/or other linear movement structures to effectmovement and positioning of the second shield plate 58 relative to thefirst shield plate 52. Since stepper motors are conventionalelectro-mechanical devices, further description is omitted for the sakeof brevity.

The housing 60 a of the second positioning device 60 is fixedly attachedto the lower surface 52 b of the first shield plate 52. The shaft 60 bis connected to the slider 56 b. Since the slider 56 b is rigidly fixedto the second shield plate 58, movement of the slider 56 b by the firstpositioning device 60 causes corresponding linear movement of the secondshield plate 58 along the second axis A₂.

The first shield plate 52 and the second shield plate 58 are sized andconfigured such that at least one of (and in the depicted body both) thefirst shield plate 52 and the second shield plate 58 is positionedbetween the transmission coil 22 and the vehicle body structure 29throughout the entire range of movement of the first shield plate 52 andthe second shield plate 58 when the vehicle-side induction coil 62 is inat least partial alignment with the transmission coil 22. The size anddimensions of the first shield plate 52 and the second shield plate 58is such that they are both located between the vehicle body structure 29and the transmission coil 22 with the vehicle-side induction coil 62being positioned relative to the transmission coil 22 with thevehicle-side induction coil 62 having an efficiency of reception ofelectromagnetic radiation from the transmission coil that is equal to orgreater to a predetermined level of efficiency, as described furtherbelow.

As shown in FIGS. 3 and 4, the vehicle-side induction coil 62 is fixedlyattached to the lower surface 58 b (the second side) of the secondshield plate 58. The vehicle-side induction coil 62 is configured togenerate electric current in response reception of electromagneticradiation transmitted from the transmission coil 22. The overall sizeand dimensions of the vehicle-side induction coil 62 are determinedbased upon the charging power needs of the battery B of the vehicle 14and the capabilities of the transmission coil 22. However, in thedepicted embodiment the vehicle-side induction coil 62 has an outerdiameter of between 25.0 cm and 35.0 cm. Further, the diameter of thevehicle-side induction coil 62 can be 30.0 cm.

A description is now provided of the operation of the wireless chargingstructure 10. As shown in FIGS. 1 and 2, the power controller 20 and thetransmission coil 22 are electrically connected to one another by thecable C. As is explained below, the power controller 20 is configured totransmit and receive signals transmitted from the controller 32 of thevehicle 14. The power controller 20 is also configured to control thelevel of electromagnetic energy (electromagnetic radiation) emitted bythe transmission coil 22. Further, as shown in FIGS. 1, 3 and 4, thecontroller 32 is electronically connected to the battery B, the firstpositioning device 54 (a stepper motor) and the second positioningdevice 60 (another stepper motor). The controller 32 is configured tooperate the first and second positioning devices 54 and 60 to move andposition the first shield plate 52 and the second shield plate 58relative to the vehicle 14 in order to optimize the position of thevehicle-side induction coil 62 relative to the transmission coil 22. Inother words, the controller 32 is configured and programmed to align thecenter of the vehicle-side induction coil 62 with the center of thetransmission coil 22 in order to maximize the vehicle-side inductioncoil 62 reception of electromagnetic radiation transmitted by thetransmission coil 22.

FIG. 8 is a flowchart that shows basic operational steps conducted bythe power controller 20 in the control of the transmission coil 22. Thepower controller 20 can include a power switch (not shown) or caninclude a power reduction circuit that powers down the power controller20 when not in use for a predetermined period of time. In a powerreduction mode, the power controller 20 is in a standby mode, asindicated in step S1 in FIG. 8. At step S2, the power controller 20monitors the transmission coil 22 via, for example, wirelesscommunication or by detecting electromagnetic field disturbances at thetransmission coil 22 in order to determine whether or not a vehicle 14with the vehicle-side induction coil 62 has parked over the transmissioncoil 22, and further determines whether or not the battery B is in needof charging. The operation in step S2 can include wireless communicationsignals sent back and forth between the vehicle-side induction coil 62and the transmission coil 22 (i.e., “handshakes”). More specifically,the transmission coil 22 can receive signals transmitted from thevehicle-side induction coil 62 or other electronic communicationcircuitry (not shown) within the vehicle 14 in order for the powercontroller 20 to determine whether or not the vehicle 14 is parked inthe parking area P and determine whether or not the battery B needs tobe charged.

Further, the power controller 20 is activated and leaves the standbymode via any one of the following: a signal from a vehicle operator viaa wireless communication device; a mechanical electrical switch on oradjacent to the power controller 20; or detection by the powercontroller 20 of the presence of the vehicle-side induction coil 62 ofthe vehicle 14 being parked above the transmission coil 22.

At step S2, if the power controller 20 determines that the vehicle 14 ispresent and that the battery B needs charging, operation moves to stepS3. Otherwise, the power controller 20 returns to the standby mode instep S1.

At step S3, the power controller 20 sends a predetermined level of powerto the transmission coil 22 causing the transmission coil 22 to transmita low energy of electromagnetic energy charge to the vehicle-sideinduction coil 62 that signals the controller 32 via the vehicle-sideinduction coil 62. In response, the controller 32 of the vehicle 14checks the alignment between the transmission coil 22 and thevehicle-side induction coil 62 in the process described below withrespect to the flowcharts depicted in FIGS. 9-11.

At step S4, the power controller 20 checks to see if a signal has beenreceived from the controller 32 indicating alignment between thetransmission coil 22 and the vehicle-side induction coil 62. The powercontroller 20 uses the signal in order to determine whether or not thetransmission coil 22 and the vehicle-side induction coil 62 areacceptably aligned with one another. At step S4, if the power controller20 determines that the transmission coil 22 and the vehicle-sideinduction coil 62 are not yet aligned, operation returns to step S3where the low level of electromagnetic energy continues to thetransmitted by the transmission coil 22. At step S4 if the powercontroller 20 determines that the transmission coil 20 and thevehicle-side induction coil 62 are acceptably aligned, then operationmoves to step S5. At step S5, the power controller 20 causes thetransmission coil 20 to increase the level of transmission ofelectromagnetic energy to a level that enables charging of the batteryB. At step S6, the power controller 20 continues to cause thetransmission coil 20 to emit the increased level of transmission ofelectromagnetic energy in order to continue charging the battery B.

At step S7, the power controller 20 determines whether or not thebattery B is fully charged or not based on a signal or signals from thecontroller 32 of the vehicle 14. If the battery is not fully charged,control returns to step S6 and the power controller 20 continues tocause the transmission coil 20 to emit the level of transmission ofelectromagnetic energy in order to continue charging the battery B. Ifthe power controller 20 determines that the battery B is fully chargedbased on a signal or signals from the controller 32 of the vehicle 14,then operation moves to step S8, where the power controller 20 reducesor completely cuts power to the transmission coil 20 thereby ceasingcharging of the battery B. Thereafter operation returns to step S1,where the power controller 20 goes back to standby mode. It should beunderstood from the drawings and description herein, that the powercontroller 20 can also continue to monitor the status of the battery B,and perform periodic battery tending, where charging is resumed after apredetermined period of time to ensure the battery G is maintained at amaximum charge.

A description is now provided for operation of the reception chargingassembly 16 of the vehicle 14 with specific reference to FIGS. 9-11.During normal operation of the vehicle 14, the reception chargingassembly 16 is inactive and remains stationary relative to the vehicle14, except that the controller 32 monitors the condition of the batteryB. Specifically, the controller 32 monitors the level of the chargebeing maintained by the battery B. If the battery B is nearing adepletion state, the controller 32 can provide such information to thevehicle operator indicating that battery charging will soon benecessary. Otherwise, the controller 32 is maintained in the standbymode, as indicated in step S10 of FIG. 9.

At step S10, the controller 32 leaves the standby mode automatically inthe event that the vehicle 14 has been parked and shut off. Thereafter,the controller 32 moves to step S11 where the controller 32 determineswhether or not the vehicle 14 has been parked in a charging station,such as the parking area P depicted in FIG. 1. As mentioned above, thestops 24 are installed to the surface S of the parking area P in orderto provide the vehicle operator with an approximate location in which topark the vehicle 14. Thus, when parking the vehicle 14, it is assumedthat the front wheels 28 of the vehicle 14 contact the stops 24. Whenparked in this manner, the vehicle-side induction coil 62 should belocated above the transmission coil 22, but may not be perfectlyaligned. The vehicle-side induction coil 62 is therefore in anapproximate alignment position with at least a portion of thevehicle-side induction coil 62 overlapping the transmission coil 22, asviewed from above, as shown in FIG. 2.

In step S11, if the vehicle 14 has not been parked in the parking areaP, operation returns to step S10 and the standby mode. If the controller32 determines at step S11 that the vehicle 14 has been parked in acharging station, the controller 32 then determines whether or not thetransmission coil 22 is present and activated by transmission of a lowlevel of electromagnetic energy or radiation. The controller 32 and/orthe vehicle-side induction coil 62 is configured to transmit signals toand receive signals from the transmission coil 22 and/or the powercontroller 20 in order to determine the status of the output of thetransmission coil 22.

At step S12, if the transmission coil 22 is detected to be emitting alow level of electromagnetic energy (radiation) for purposes of aligningthe vehicle-side induction coil 62 with the transmission coil 22,operation moves to step S13. If the controller 32 determines that noenergy is being emitted by the transmission coil 22, then operationsreturn to step S10 and the standby mode.

At step S13, the controller 32 determines whether or not thetransmission coil 22 and the vehicle-side induction coil 62 are alignedwithin predetermined parameters to allow efficient charging of thebattery B. If the transmission coil 22 and the vehicle-side inductioncoil 62 are not aligned to the predetermined parameters, then operationmoves to step S14 where the aligning procedures set forth in theflowcharts in FIGS. 10 and 11 are conducted, as described below. Afterthe aligning procedures are completed, operation returns to step S13. Ifthe transmission coil 22 and the vehicle-side induction coil 62 are notaligned to the predetermined parameters, operation can then again moveto step S14. If the transmission coil 22 and the vehicle-side inductioncoil 62 are aligned to the predetermined parameters, then operationmoves to step S15.

At step S14, a safeguard can be included that stops the alignmentprocess from repeating indefinitely. The safeguard includes a signal tothe vehicle operator that there may be a problem, such as the vehicle 14may be parked in such a way that the vehicle-side induction coil 62 istoo far away from the transmission coil 22 to enable optimalelectromagnetic energy exchange between the transmission coil 22 and thevehicle-side induction coil 62.

At step S15, the controller 32 and/or the vehicle-side induction coil 62transmits a signal to the transmission coil 22 and/or the powercontroller 20 indicating that charging can commence. In response, asmentioned above with respect to step S5 in FIG. 8, the power controller20 increases the output of electromagnetic radiation from thetransmission coil 22 thereby enabling charging of the battery B. In stepS16, the controller 32 determines whether or not the battery B is fullycharged. If the battery is not fully charged, operation returns to stepS15 and charging continues. If the battery is fully charged in step S16,then the controller 32 and/or the vehicle-side induction coil 62transmits a signal to the transmission coil 22 and/or the powercontroller 20 indicating that charging is completed. Thereafter, thecontroller 32 returns to the standby mode in step S10.

Upon moving from step S16, the controller 32 can be configured in any ofa variety of manners. For example, as described further below, thecontroller 32 operates the first and second positioning devices 54 and60. At the conclusion of the charging operation at step S16, thecontroller 32 can operate the first and second positioning devices 54and 60 to return to a start position where the vehicle-side inductioncoil 62 is centered with respect to the alignment assembly 34.

Alternatively, upon moving from step S16, the controller 32 can beconfigured to lock the first and second positioning devices 54 and 60thereby preventing any movement of the vehicle-side induction coil 62.This locking procedure can be advantageous if the vehicle 14 is alwaysparked in the same charging station. The vehicle operator may be able topark the vehicle 14 in a position within the parking area P such thatthe alignment procedure is minimal or not necessary when the vehicle 14is parked.

Description now moves to the steps outlined in FIG. 10, where thecontroller 32 manages the alignment procedure of the vehicle-sideinduction coil 62 relative to the transmission coil 22.

At step S20, the controller 32 enters an alignment management mode fromoperations at step S14 in FIG. 9. Operation immediately moves to stepS21. At step S21, the controller 32 sets a variable “increment” thatcorresponds to stepper motor movement to a predetermined upper presetlevel. This step defines the increment of movement each time each of thefirst and second positioning devices 54 and 60 is operated to repositionthe first shield plate 52 and the second shield plate 58. The upperpreset level of the “increment” of movement of each of the steppermotors of the first and second positioning devices 54 and 60 isdetermined based upon the overall dimensions of the alignment assembly34, the precision and tolerances of the first and second positioningdevices 54 and 60 and tolerances of the first and second track structure50 and 56. The upper preset level is provided in order to make thealignment process more efficient. For example, the upper present levelcan be between 2 mm and 20 mm, depending upon the overall tolerances ofthe various components of the alignment assembly 34.

Step S21 is basically an initialization of the variable “increment.” Thevalue of “increment” can be reduced by the controller 32 at step 27, asis explained in greater detail below.

Once the variable “increment” has been initialized, operation then movesto step S22 where the controller 32 determines whether or not the valueof “increment” is too low or not. Initially, the value of “increment” isinitialized at a maximum value defined as the upper preset level. Thecontroller 32 is programmed with a minimum value of “increment” and thecurrent value is compared with the minimum value. If the minimum valuesis equal to or greater than the current value of “increment” thenoperation moves to step S23, and a signal is sent to the vehicleoperator that there is a problem with alignment, such as thevehicle-side induction coil 62 being too far out of alignment with thetransmission coil 22 requiring re-parking of the vehicle 14 within theparking area P. If the minimum values is less that the current value of“increment” then operation moves to step S24.

At step S24, the controller 32 defines a “designated axis” for alignmentmovement as being the first axis A₁ (movement in the vehiclelongitudinal direction D_(L)). Consequently, the first iteration of thesteps in FIG. 11 will involve movement of the first shield plate 52along the first track structure 50 via control of operation of the firstpositioning device 54. Once the “designated axis” is defined as movementin the first axis A₁, operation moves to FIG. 11, as described ingreater detail below. The movements of the vehicle-side induction coil62 conducted by the controller 32 with the “designated axis” foralignment movement being the first axis A₁ (the vehicle longitudinaldirection D_(L)) are demonstrated in FIGS. 12a thru 12 e, as is alsodescribed in greater detail below. When the first iteration of FIG. 11is completed relative to the first axis A₁, control moves to step S25.

At step S25, the controller 32 defines the “designated axis” foralignment movement as being the second axis A₂ (extending in the vehiclelateral direction D_(S)). Consequently, the second iteration of thesteps in FIG. 11 will involve movement of the second shield plate 56along the second track structure 56 via control of operation of thesecond positioning device 60. Once the “designated axis” is defined asmovement along the second axis A₂, operation moves again to FIG. 11, butwith the controller 32 operating the second positioning device 60. Themovements of the vehicle-side induction coil 62 conducted by thecontroller 32 with the “designated axis” for alignment movement beingalong the second axis A₂ (in the vehicle lateral direction D_(S)) aredemonstrated in FIGS. 13a thru 13 e, as is also described in greaterdetail below. When the second iteration of FIG. 11 is completed relativeto the second axis A₂ (the slider 56 b), control moves to step S26.

At step S26, the controller 32 determines whether or not the movementsof the first and second positioning devices 54 and 60 were too large byevaluating the efficiency level. Specifically, if the movements of thefirst and second positioning devices 54 and 60 did not achieve adequatealignment, and may not have provided small enough movements to properlyalign the vehicle-side induction coil 62 with the transmission coil 22,then the efficiency level will not be acceptable and the controller 32moves to step S27 where the controller 32 reduces the size of thevariable “increment,” thereby making each movement of the first andsecond positioning devices 54 and 60 smaller. The “increment” caninitially be defined as, for example, 1 cm (10 mm), depending upon thetolerances of the overall apparatus and the tolerances of the first andsecond positioning devices 54 and 60. Alternatively, the “increment” canbe greater than 10 mm or less than 10 mm.

If at step S26, the controller 32 determines that the efficiency levelis acceptable indicating that the movements of the first and secondpositioning devices 54 and 60 were acceptable, and the vehicle-sideinduction coil 62 and the transmission coil 22 are adequately aligned,control moves to step S28.

As step S28, the controller 32 sends a signal to the power controller 20indicating that the vehicle-side induction coil 62 and the transmissioncoil 22 are properly aligned. At this point, the power controller 20 iswaiting at step S4 in FIG. 8 and moves to step S5 where power to thetransmission coil 22 is increased to a level corresponding to chargingof the battery B. Once the controller 32 determines that thetransmission coil 22 is emitting a charging level of electromagneticradiation, the controller 32 enables the vehicle-side induction coil 62to receive the power from the transmission coil 22. The controller 32further enables its circuitry to convert the alternating current energytransmitted from the transmission coil 22 to the vehicle-side inductioncoil 62 into direct current and providing that direct current to thebattery B thereby charging the battery B. Operation then moves to stepS29 where the logic returns to FIG. 9 completes step S14.

A description is now provided of the operational steps depicted in FIG.11. The operational steps in FIG. 11 are used twice during the overalloperation of the alignment assembly 34. As mentioned above, at step S24in FIG. 10, the “designated axis” is defined as being the first axis A₁.Therefore, movement and positioning of the vehicle-side induction coil62 will be in the vehicle longitudinal direction D_(L). Further, thecontroller 32 operates the first positioning device 54 to move andposition the first shield plate 52 in order to align the vehicle-sideinduction coil 62 with the transmission coil 22 along the first axis A₁.Consequently, during the first iteration of the steps in FIG. 11, thevehicle-side induction coil 62 is moved and positioned relative to thefirst axis A₁ (in the vehicle longitudinal direction D_(L)) asdemonstrated in FIGS. 12a thru 12 e. Thereafter at step S25 in FIG. 10,the “designated axis” is defined as being the second axis A₂. Therefore,movement and positioning of the vehicle-side induction coil 62 will bein the vehicle lateral direction D_(S). Further, the controller 32operates the second positioning device 60 to move and position thesecond shield plate 58. Consequently, during the second iteration of thesteps in FIG. 11, the vehicle-side induction coil 62 is moved andpositioned along the second axis A₂ (in the vehicle lateral directionD_(S)) as demonstrated in FIGS. 13a thru 13 e.

The following description of operations in FIG. 11 is carried out withthe “designated axis” extending along the first axis A₁ (the slider 50b), corresponding to the vehicle longitudinal direction D_(L). At stepS30 in FIG. 11, the controller 32 starts the alignment procedure for thedesignated axis. At this time, the transmission coil 22 is emitting apredetermined lowered level of electromagnetic radiation for purposes ofaligning the vehicle-side induction coil 62 with the transmission coil22 (as per step S3 in FIG. 8). At step S31, the controller 32 measuresthe amount of electromagnetic radiation being received by thevehicle-side induction coil 62 and determines the efficiency of thereception of the electromagnetic radiation. The controller 32 is eitherpre-programmed with the predetermined lowered level of electromagneticradiation and/or receives a signal from the power controller 20 withinformation regarding the predetermined lowered level of electromagneticradiation.

At step S31, the controller 32 determines whether or not the efficiencyof the reception of the electromagnetic radiation meets an acceptablepredetermined efficiency level. If the efficiency level of the receptionof electromagnetic radiation is at or above the acceptable predeterminedefficiency level, then no alignment is necessary and control moves tostep S32 and returns to the operations in FIG. 10. If the efficiencylevel of the reception of electromagnetic radiation is below theacceptable predetermined efficiency level, then alignment is necessaryand control moves to step S33.

At step S33; the controller 32 operates the first positioning device 54(the stepper motor) to move the slider 50 b in a first direction alongthe first axis A₁ (in the vehicle longitudinal direction D_(L)) adistance equivalent to the defined “increment.” The shaft 54 a of thefirst positioning device 54 is fixed to the slider 50 b and the slider50 b is fixed to the first shield plate 52. Consequently, movementeffected by the first positioning device 54 translates into a firstmovement M₁ of the vehicle-side induction coil 62 along the first axisA₁. FIG. 12a shows an example of the position of the vehicle-sideinduction coil 62 relative to the transmission coil 22 when the vehicle14 is parked in the parking area P. In FIG. 12a , the vehicle-sideinduction coil 62 is in the approximate alignment position mentionedabove, and is therefore mis-aligned with the transmission coil 22. FIG.12b shows the vehicle-side induction coil 62 moved by operation of thefirst positioning device 54 at step S33 as indicated by the firstmovement M₁. As can be seen by comparing FIG. 12a with FIG. 12b , thevehicle-side induction coil 62 has moved along the first axis A₁ (thevehicle longitudinal direction D_(L)).

Next, at step S34 in FIG. 11, the controller 32 determines whether ornot the efficiency level has improved. If the efficiency level has notimproved, operation moves to step S40, described further below. If theefficiency level has improved, operation moves to step S35.

At step S35, the controller 32 determines whether or not the efficiencylevel is now acceptable (at or above the acceptable predeterminedefficiency level). If the efficiency level is acceptable, operationmoves to step S32 and back to the steps in FIG. 10. If the efficiencylevel is not acceptable, operation moves to step S36.

At step S36, the controller 32 again operates the first positioningdevice 54 to move the slider 50 b again by a distance approximatelyequivalent to the defined “increment.” FIG. 12b shows the position ofthe vehicle-side induction coil 62 after the first movement M₁ is madeat step S33. FIG. 12c shows the vehicle-side induction coil 62 after asecond movement M₂ made at step S36. As can be seen by comparing FIG.12b with FIG. 12c , the vehicle-side induction coil 62 has made thesecond movement M₂ further along the first axis A₁ (in the vehiclelongitudinal direction D_(L)) relative to the transmission coil 22.

Next at step S37, the controller 32 determines again whether or not theefficiency level has improved. If the efficiency level has not improved,operation moves to step S38, described below. If the efficiency levelhas improved, operation returns to step S36, where third movement M₃ ofthe vehicle-side induction coil 62 is made by the controller 32. Fordemonstration purposes in the following description of FIGS. 12c and 12d, it is assumed that in step S37 the controller 32 determined that theefficiency level improved and control has returned again to Step S36where the third movement M₃ of the vehicle-side induction coil 62 isconducted. FIG. 12c shows the position of the vehicle-side inductioncoil 62 after the second movement M₂ is made in the first passingthrough step S36. FIG. 12d shows the vehicle-side induction coil 62after the third movement M₃ is made during a second passing through atstep S36. As can be seen by comparing FIG. 12c with FIG. 12d , thevehicle-side induction coil 62 has moved further along the first axis A₁(in the vehicle longitudinal direction D_(L)) relative to thetransmission coil 22. However, FIG. 12d appears to show that thevehicle-side induction coil 62 is now moved to a position that does notimprove efficiency.

Operation again moves to step S37 where the controller 32 determinesthat the efficiency level has not improved, operation now moves to stepS38. At step S38, the controller 32 causes the first positioning device54 to return the vehicle-side induction coil 62 back to its previousposition via a fourth movement M₄, as shown in FIG. 12e . As is shown inFIG. 12e , the fourth movement M₄ is in a direction that is opposite thefirst movement M₁, the second movement M₂ and the third movement M₃.

Thereafter, operation moves to step S39 where operations return to FIG.10.

Returning to Step S34, if the controller 32 determines that theefficiency level has not improved, operation moves to step S40 where thevehicle-side induction coil 62 is moved back to its previous position(its initial position). Step S40 thru step S46 basically deal with thesituation where the movement of the vehicle-side induction coil 62 toimprove efficiency is in a direction corresponding the direction of thefourth movement M₄. Specifically, the first movement M₁, the secondmovement M₂ and the third movement M₃ are all movements in a firstdirection relative to the first axis A₁. The fourth movement M₄ is in asecond direction opposite the first direction.

At step S41, the controller 32 causes the first positioning device 54 tomove the slider 50 b, the first shield plate 52 and the vehicle-sideinduction coil 62 in the second direction opposite the first directionalong the first axis A₁ (a movement in the same direction as the fourthmovement M₄). At step S42, the controller 32 determines whether or notthe efficiency level has not improved. If the efficiency level hasimproved, operation moves to step S38. If the efficiency has notimproved, operation moves to step S43.

At step S43, the controller 32 again causes the first positioning device54 to move the slider 50 b, the first shield plate 52 and thevehicle-side induction coil 62 in the second direction opposite thefirst direction along the first axis A₁ (a movement in the samedirection as the fourth movement M₄). At step S44, the controller 32again determines whether or not the efficiency level has not improved.If the efficiency level has improved, operation moves to step S43, suchthat steps S43 and S44 are repeated. If the efficiency has not improved,operation moves to step S45.

At step S45 the controller, moves the slider 50 b, the first shieldplate 52 and the vehicle-side induction coil 62 back to a position priorto the most recent movement thereof. At step S46, operation returns toFIG. 10 and step S25.

At step S25 in FIG. 10, the “designated axis” is defined and the secondaxis A₂ and operation moves back again to the flowchart in FIG. 11. Allof the steps in FIG. 11 are repeated, but with all movements being madeby the second positioning device 54 and along the second axis A₂ only.Since the steps in FIG. 11 are unchanged, except that movement is alongthe second axis A₂, further description is omitted for the sake ofbrevity. However, examples of the movements along the second axis A₂ ofthe vehicle-side induction coil 62 made during the second iteration ofFIG. 11 are depicted in FIGS. 13a thru 13 e.

Specifically, during the iteration of the steps in FIG. 11 with the“designated axis” being the second axis A₂, at step S33 the controller32 operates the second positioning device 60 (the stepper motor) to movethe slider 56 b in a first direction along the second axis A₂ (in thevehicle lateral direction D_(S)) a distance equivalent to the defined“increment.” Movement of the shaft 60 a of the second positioning device60 (the shaft 60 a is fixed to the slider 50 b and the slider 50 b isfixed to the first shield plate 52) causes a first movement M₁₀ of thevehicle-side induction coil 62 along the second axis A₂, from therelative positions shown in FIG. 13a to the positions shown in FIG. 13b.

FIG. 13a shows the vehicle-side induction coil 62 relative to thetransmission coil 22 after completion of the alignment steps describedabove with respect to positioning movement with the first axis A₁ beingthe “designated axis.” FIG. 13b shows the vehicle-side induction coil 62moved by operation of the second positioning device 60 at step S33 asindicated by the first movement M₁₀ with the second axis A₂ being the“designated axis.” As can be seen by comparing FIG. 13a with FIG. 13b ,the vehicle-side induction coil 62 has moved along the second axis A₂(the vehicle lateral direction Ds).

At step S36 in FIG. 11 with the second axis A₂ being the “designatedaxis,” the controller 32 again operates the second positioning device 60to move the slider 56 b again by a distance approximately equivalent tothe defined “increment.” FIG. 13b shows the position of the vehicle-sideinduction coil 62 after the first movement M₁₀ made at step S33. FIG.13c shows the vehicle-side induction coil 62 after a second movement M₁₁made at step S36. As can be seen by comparing FIG. 13b with FIG. 13c ,the vehicle-side induction coil 62 has moved in the second movement M₁₁further along the second axis A₂ relative to the transmission coil 22.

If the operation in step S36 in FIG. 11 is repeated, a third movementM₁₂ of the vehicle-side induction coil 62 along the second axis A₂ ismade by the controller 32, as indicated in FIG. 13d . If the controllerhas determined that the third movement M₁₂ does not improve transmissionefficiency, at step S38, the controller 32 causes the second positioningdevice 60 to return the vehicle-side induction coil 62 back to itsprevious position via a fourth movement M₁₃, as shown in FIG. 13e . Asis shown in FIG. 13e , the fourth movement M₁₃ is in a direction that isopposite the first movement M₁₀, the second movement M₁₁ and the thirdmovement M₁₂. In FIG. 11 at steps S38, S40 and S43, with the second axisA₂ being the “designated axis,” the controller 32 causes the secondpositioning device 60 to move the slider 56 b, the second shield plate58 and the vehicle-side induction coil 62 in a second direction oppositethe first direction along the second axis A₂.

As described above, the controller 32 is configured to operate the firstpositioning device 54 to linearly move and position the vehicle-sideinduction coil 62 along the first axis A₁ in order to more closely alignthe vehicle-side induction coil 62 with the transmission coil 22relative to the first axis A₁. Thereafter, the controller 32 isconfigured to operate the second positioning device 60 to move andposition the vehicle-side induction coil 62 along the second axis A₂ inorder more closely align the vehicle-side induction coil 62 with thetransmission coil 22 relative to the second axis A₂. If first attemptsat alignment fail to yield a predetermined efficiency level, the“increment” of movement along each of the first and second axis A₁ andA₂ can be reduced to further refine the movement of the vehicle-sideinduction coil 62 along each of the first and second axis A₁ and A₂.

The efficiency level used by the controller 32 at, for example, step S26in FIG. 10, is preferably above 80% efficiency. Specifically, at least80% of the electromagnetic energy outputted by the transmission coil 22is received by the vehicle-side induction coil 62 and converted intodirect current to charge the battery B. However, the efficiency level ismore preferably 90%.

If a center of the vehicle-side induction coil 62 is not aligned with acenter of the transmission coil 22 by, for example, 50% of the overalldiameter of the transmission coil 22, efficiency of energy transmittancecan be below 60%, making consumption of energy to operate thetransmission coil 22 very inefficient. If the center of the vehicle-sideinduction coil 62 is not aligned with a center of the transmission coil22 by, for example, 25% of the overall diameter of the transmission coil22, efficiency of energy transmittance can be below 80%, makingconsumption of energy to operate the transmission coil 22 moreefficient, but still not an optimal efficiency. After using the abovedescribed alignment procedures, efficiency is improved. In the preferredembodiment, a 90% rate of efficiency is expected. More specifically, anacceptable predetermined efficiency level is 90% where 90% of theelectromagnetic radiation emitted by the transmission coil 22 isreceived by the vehicle-side induction coil 62.

In the depicted embodiment, the transmission coil 22 and thevehicle-side induction coil 62 each have a diameter of approximately 31cm (310 mm or approximately 1.0 foot in diameter). In the depictedembodiment, the vehicle-side induction coil 62 can be moved along thefirst axis A₁ (along the first track structure 50) approximately 150 mmin each direction from a centered position (centered relative to thefirst track structure 50). Thus, the vehicle-side induction coil 62 canbe moved along the first axis A₁ a distance approximately equal to thediameter of each of the transmission coil 22 and the vehicle-sideinduction coil 62. Similarly, the vehicle-side induction coil 62 can bemoved along the second axis A₂ (along the second track structure 56)approximately 150 mm in each direction from a centered position(centered relative to the first track structure 50). Thus, thevehicle-side induction coil 62 can be moved along the second axis A₂ adistance approximately equal to the diameter of each of the transmissioncoil 22 and the vehicle-side induction coil 62. Consequently, as long asthe vehicle 14 is parked within the parking area P with at least aportion of the vehicle-side induction coil 62 overlapping with thetransmission coil 22, the controller 32 can manipulate the first andsecond positioning devices 54 and 60 to bring the vehicle-side inductioncoil 62 into alignment with the transmission coil 22.

It should be understood from the drawings and the description herein,that above mentioned dimensions of the transmission coil 22, thevehicle-side induction coil 62 and the elements of the alignmentassembly 34 can be scaled and redesigned in order to accommodate therecharging needs of any of a variety of shapes and designs of vehiclesthat require regular recharging of batteries. Specifically, outerdiameters of the transmission coil 22 and the vehicle-side inductioncoil 62 is not limited to the diameter mentioned above. The transmissioncoil 22 and the vehicle-side induction coil 62 need not be the samediameter and can be larger or smaller depending upon the rechargingrequirements of the vehicle. Further, the lengths of the first andsecond track structures 50 and 56, and the overall dimensions of thefirst and second shield plates 52 and 58 can vary depending upon thedesired position adjustment ranges of the first and second trackstructures 50 and 56.

Further, the first and second track structures 50 and 56 depicted in thefirst embodiment can be re-designed and reconfigured depending upon theoverall design of the wireless charging structure 10 and the vehicle 12.For instance, in some designs only one of each of the linear supportstructures 64 and 66 might be necessary. Further, in the depictedembodiment, the first positioning device 54 is attached to the slider 50b and directly moves the slider 50 b, and, the second positioning device60 is attached to the slider 56 b and directly moves the slider 56 b. Inan alternative embodiment (the second embodiment), the first positioningdevice 54 can be directly attached to the first shield plate 52 and thesecond positioning device 60 can be directly attached to the secondshield plate 58. As well, the first and second track structure 50 and 56can be oriented to position the first and second shield plates 52 and 58in directions other than those depicted in the drawings. For example,the first track structure 50 can be oriented to position the firstshield plate 52 along the vehicle lateral directions D_(s) and thesecond track structure 56 can be oriented to position the second shieldplate 58 along the vehicle longitudinal directions D_(L).

Further, in the above described embodiment, the order of alignment canbe reversed such that the second positioning device 60 is operated toadjust the position the second shield plate 58 and thereafter the firstpositioning device 54 is operated to adjust the position the firstshield plate 52.

Second Embodiment

Referring now to FIG. 14, the alignment assembly 34 in accordance with asecond embodiment will now be explained. In view of the similaritybetween the first and second embodiments, the parts of the secondembodiment that are identical to the parts of the first embodiment willbe given the same reference numerals as the parts of the firstembodiment. Moreover, the descriptions of the parts of the secondembodiment that are identical to the parts of the first embodiment maybe omitted for the sake of brevity. The parts of the second embodimentthat differ from the parts of the first embodiment will be indicatedwith a single prime (′).

The alignment assembly 34 includes all of the features of the firstembodiment, including the first track structure 50 (with the fixed trackmember 50 a and the slider 50 b), the linear support structures 64 (withrespective upper sliders 64 a and lower sliders 64 b), the first shieldplate 52, the second track structure 56 (with the fixed track member 56a and the slider 56 b), the linear support structures 66 (withrespective upper sliders 66 a and lower sliders 66 b), the second shieldplate 58, and the vehicle-side induction coil 62. All of the abovelisted elements are as described above with respect to the firstembodiment.

In the second embodiment, the first positioning device 54 is replacedwith a first positioning device 54′ and the second positioning device 60is replaced with a second positioning device 60′.

The first positioning device 54′ includes a housing 54 a′ that is fixedto the underside surface 44 of the vehicle 14 and a shaft 54 b′ that isdirectly attached to the first shield plate 52. Hence, the firstpositioning device 54′ directly moves and positions the first shieldplate 52 along the first axis A₁. It should be understood from thedrawings and the description herein that the first shield plate 52 isslidably supported by the first track structure 50 and is free to movealong the first axis A₁ and is only constrained against such movement bythe first positioning device 54′.

Further in the second embodiment, the second positioning device 60′includes a housing 60 a′ that is fixed to the first shield plate 52 anda shaft 60 b′ that is directly attached to the second shield plate 58.Hence, the second positioning device 60′ directly moves and positionsthe second shield plate 58 along the second axis A₂. It should beunderstood from the drawings and the description herein that the secondshield plate 58 is slidably supported by the second track structure 56and is free to move along the second axis A₂ and is only constrainedagainst such movement by the second positioning device 60′.

The power controller 20 and the controller 32 each preferably includes amicrocomputer with respective alignment control programs that controlcorresponding features of the wireless charging structure 10, asdiscussed above. The power controller 20 and the controller 32 can eachalso include other conventional components such as an input interfacecircuit, an output interface circuit, and storage devices such as a ROM(Read Only Memory) device and a RAM (Random Access Memory) device. Themicrocomputers of the power controller 20 and the controller 32 are eachprogrammed to control the respective portions of wireless chargingstructure 10. The memory circuits store processing results and controlprograms such as ones for wireless charging operations that are run bythe processor circuits. The power controller 20 is operatively coupledto the transmission coil 22 in a conventional manner and the controller32 is operatively coupled to the alignment assembly 34 and thevehicle-side induction coil 62 in conventional manners. The internal RAMof each of the power controller 20 and the controller 32 store statusesof operational flags and various control data. The internal ROMs of eachof the power controller 20 and the controller 32 store the wirelesscharging protocols and alignment movement controls for various theoperations described above. It will be apparent to those skilled in theart from this disclosure that the precise structure and algorithms foreach of the power controller 20 and the controller 32 can be anycombination of hardware and software that will carry out the functionsof the present invention.

The various features of the vehicle 14 are conventional components thatare well known in the art. Since vehicle components are well known inthe art, these structures will not be discussed or illustrated in detailherein. Rather, it will be apparent to those skilled in the art fromthis disclosure that the components can be any type of structure and/orprogramming that can be used to carry out the present invention.

GENERAL INTERPRETATION OF TERMS

In understanding the scope of the present invention, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including,” “having” and theirderivatives. Also, the terms “part,” “section,” “portion,” “member” or“element” when used in the singular can have the dual meaning of asingle part or a plurality of parts. Also as used herein to describe theabove embodiments, the following directional terms “forward,”“rearward,” “above,” “downward,” “vertical,” “horizontal,” “below” and“transverse” as well as any other similar directional terms refer tothose directions of a vehicle equipped with the wireless chargingstructure 10. Accordingly, these terms, as utilized to describe thepresent invention should be interpreted relative to a vehicle equippedwith the wireless charging structure 10.

The term “detect” as used herein to describe an operation or functioncarried out by a component, a section, a device or the like includes acomponent, a section, a device or the like that does not requirephysical detection, but rather includes determining, measuring,modeling, predicting or computing or the like to carry out the operationor function.

The term “configured” as used herein to describe a component, section orpart of a device includes hardware and/or software that is constructedand/or programmed to carry out the desired function.

The terms of degree such as “substantially,” “about” and “approximately”as used herein mean a reasonable amount of deviation of the modifiedterm such that the end result is not significantly changed.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. For example, the size, shape, location ororientation of the various components can be changed as needed and/ordesired. Components that are shown directly connected or contacting eachother can have intermediate structures disposed between them. Thefunctions of one element can be performed by two, and vice versa. Thestructures and functions of one embodiment can be adopted in anotherembodiment. It is not necessary for all advantages to be present in aparticular embodiment at the same time. Every feature which is uniquefrom the prior art, alone or in combination with other features, alsoshould be considered a separate description of further inventions by theapplicant, including the structural and/or functional concepts embodiedby such features. Thus, the foregoing descriptions of the embodimentsaccording to the present invention are provided for illustration only,and not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

What is claimed is:
 1. An alignment method for a vehicle wirelesscharging system, the method comprising: detecting reception ofelectromagnetic radiation received by a vehicle-side coil from atransmitter coil with the vehicle-side coil at a current positionrelative to the transmitter coil; determining efficiency ofelectromagnetic radiation reception by the vehicle-side coil;determining whether or not the efficiency of electromagnetic radiationreception by the vehicle-side coil achieves a predetermined level ofreception efficiency; repositioning the vehicle-side coil in response todetermining that the efficiency of the electromagnetic radiationreception is less than the predetermined level of reception efficiency;and repeating the determining of the efficiency of electromagneticradiation reception and the repositioning the vehicle-side coil untilthe determined efficiency is equal to or greater than the predeterminedlevel of reception efficiency.
 2. The method according to claim 1,wherein the repositioning the vehicle-side coil includes moving thevehicle-side coil along a first axis that is parallel to a main surfaceof the vehicle-side coil.
 3. The method according to claim 2, whereinthe repositioning the vehicle-side coil includes moving the vehicle-sidecoil along a second axis that is also parallel to a main surface of thevehicle-side coil and perpendicular to the first axis.
 4. The methodaccording to claim 1, further comprising maintaining the vehicle-sidecoil in a stationary position in response to the determined efficiencybeing equal to or greater than the predetermined level of receptionefficiency.
 5. The method according to claim 1, further comprisingparking a vehicle above the transmitter coil of the wireless chargingsystem prior to detecting reception of electromagnetic radiation, withthe vehicle-side coil being mounted to an underside of the vehicle. 6.The method according to claim 1, further comprising moving thevehicle-side coil to a preselected position upon moving the vehicle awayfrom the transmitter coil.
 7. The method according to claim 1, furthercomprising maintaining the vehicle-side coil in position upon moving thevehicle away from the transmitter coil.
 8. An alignment method for avehicle wireless charging system, the method comprising: detectingreception of electromagnetic radiation by the vehicle-side coil from thetransmitter coil with the vehicle-side coil at a current positionrelative to the transmitter coil; determining efficiency ofelectromagnetic radiation reception by the vehicle-side coil;determining whether or not the efficiency of electromagnetic radiationreception by the vehicle-side coil achieves a predetermined level ofreception efficiency; repositioning the vehicle-side coil in a firstadjustment direction in response to determining that the efficiency ofthe electromagnetic radiation reception is less than the predeterminedlevel of reception efficiency while maintaining position of thevehicle-side coil in a second adjustment direction perpendicular to thefirst adjustment direction; and repeating the determining of theefficiency of electromagnetic radiation reception and the repositioningthe vehicle-side coil in the first adjustment direction until thedetermined efficiency is determined to be at a maximized level.
 9. Themethod according to claim 8, further comprising redefining the currentposition of the vehicle-side coil based upon movement of thevehicle-side coil during the repositioning of the vehicle-side coil;re-determining efficiency of electromagnetic radiation reception by thevehicle-side coil; determining whether or not the efficiency ofelectromagnetic radiation reception by the vehicle-side coil achievesthe predetermined level of reception efficiency; repositioning thevehicle-side coil in the second adjustment direction in response todetermining that the efficiency of the emission is less than thepredetermined level of reception efficiency while maintaining positionof the vehicle-side coil in the first adjustment direction; andrepeating the re-determining of the efficiency of electromagneticradiation reception and the repositioning the vehicle-side coil in thesecond adjustment direction until the determined efficiency isdetermined to be equal to or greater than the predetermined level ofreception efficiency.
 10. The method according to claim 8, furthercomprising parking a vehicle above the transmitter coil of the wirelesscharging system prior to detecting reception of electromagneticradiation, with the vehicle-side coil being mounted to an underside ofthe vehicle.
 11. The method according to claim 8, wherein therepositioning the vehicle-side coil in the first adjustment directionincludes operating a stepper motor coupled to the vehicle-side coil. 12.The method according to claim 8, wherein the repositioning thevehicle-side coil in the first adjustment direction includes operating afirst stepper motor coupled to the vehicle-side coil and therepositioning the vehicle-side coil in the second adjustment directionincludes operating a second stepper motor coupled to the vehicle-sidecoil.
 13. The method according to claim 8, wherein moving thevehicle-side coil to a preselected position upon moving the vehicle awayfrom the transmitter coil.
 14. The method according to claim 8, furthercomprising maintaining the vehicle-side coil in a current position uponmoving the vehicle away from the transmitter coil.
 15. An alignmentmethod for a vehicle wireless charging system, the method comprising:emitting a first level of electromagnetic radiation from the transmittercoil; detecting reception of the first level of electromagneticradiation by the vehicle-side coil from the transmitter coil with thevehicle-side coil at a current position relative to the transmittercoil; determining efficiency of electromagnetic radiation reception atthe first level by the vehicle-side coil; determining whether or not theefficiency of electromagnetic radiation reception at the first level bythe vehicle-side coil achieves a predetermined level of receptionefficiency; repositioning the vehicle-side coil in response todetermining that the efficiency of the electromagnetic radiationreception at the first level is less than the predetermined level ofreception efficiency; repeating the determining of the efficiency ofelectromagnetic radiation reception and the repositioning thevehicle-side coil until the determined efficiency of electromagneticradiation reception at the first level is determined to be equal to orgreater than the predetermined level of reception efficiency; andincreasing the electromagnetic radiation from the transmitter coil to abattery charging level in response to the determined efficiency ofelectromagnetic radiation reception at the first level being equal to orgreater than the predetermined level of reception efficiency.
 16. Themethod according to claim 15, wherein the repositioning the vehicle-sidecoil includes moving the vehicle-side coil along a first axis that isparallel to a main surface of the vehicle-side coil, and therepositioning the vehicle-side coil includes moving the vehicle-sidecoil along a second axis that is also parallel to a main surface of thevehicle-side coil and perpendicular to the first axis.
 17. The methodaccording to claim 15, further comprising maintaining the vehicle-sidecoil in a stationary position in response to the determined efficiencybeing equal to or greater than the predetermined level of receptionefficiency.
 18. The method according to claim 15, further comprisingparking a vehicle above the transmitter coil of the wireless chargingsystem prior to detecting reception of electromagnetic radiation, withthe vehicle-side coil being mounted to an underside of the vehicle. 19.The method according to claim 15, wherein the repositioning thevehicle-side coil in response to determining that the efficiency of theelectromagnetic radiation reception at the first level is less than thepredetermined level of reception efficiency includes at least one of thefollowing: repositioning the vehicle-side coil in a first adjustmentdirection in response to determining that the efficiency of theelectromagnetic radiation reception is less than the predetermined levelof reception efficiency while maintaining position of the vehicle-sidecoil in a second adjustment direction perpendicular to the firstadjustment direction; and repositioning the vehicle-side coil in thesecond adjustment direction in response to determining that theefficiency of the emission is less than the predetermined level ofreception efficiency while maintaining position of the vehicle-side coilin the first adjustment direction.